Carpet scrubbing machine



July 15, 1958 H. D. RENCH ET AL 2,842,788

CARPET SCRUBBING MACHINE 5 Sheets-Sheet 1 Filed Jan. 27. 1956 INVENTORSHARRY D. RENCH HERBERT W. HARRIS HAROLD M. KELM LOREN R. MASSIEATTORNEYS July 15, 1958 H. D. RENCH ET AL 2,842,788

CARPET SCRUBBING MACHINE Filed Jan. 27, 1956 a l 6 as 8 36' 42 as Q I I11/ 2,2 'W'J /2 F7 /23 37 u 32 2Z 3/4 Z2 Y Z 56 7? 0 28 ea 72 80 H 5sINVENTORS HARRY D.RENCH HERBERT W.HARR|S HAROLD M. KELM LOREN R.MASSIEATTORNEYS July 15, 1958 H. D. RENCH ET AL 2,842,788

CARPET SCRUBBING MACHINE Filed Jan. 27, 1956 5 Sheets-Sheet 3 HA LD M.KM LORENR.MA IE AT TORNEYS H. D. RENCH ET AL 2,842,788

July 15, 1958 CARPET SCRUBBING MACHINE 5 Sheets-Sheet 4 Filed Jan. 27,1956 HARRY D.RENCH HERBERT W.HARRIS HAROLD M. KELM LOREN R.MASSIE ATTORNEYS Jilly 1953 H. D. RENCH ETAL 2,842,788

CARPET SCRUBBING MACHINE Filed Jan. 2'7, 1956 5 Sheets-Sheet 5 1/ 77 26W INVENTORS HARRY D.RENCH 1mm 7 I 7 HERBERT W.HARRIS i I HAROLD M.KELM'755 B LORENIRMASSIE ATTORNEYS Z2 M 1 I United States Patent CARPETSCRUBBHNG MACHINE Harry I). Rench, Herbert W. Harris, and Harold M.Keirn, Racine, and Loren R. Massie, Kenosha, Win, assignors to RacineIndustrial Plant, Iuc., Racine, Wis, a corporation of WisconsinApplication January 27, 1956, Serial No. 561,756

11 Claims. (Cl. 15--48) This invention appertains to the scrubbing ofcarpets directly on the floor and one of the primary objects of theinvention is to provide a new and novel means to bring about thecleaning of carpets by the use of a portable machine embodying powerdriven brushes for effectively working dry cleaning powder back and'forth through the nap, pile or twist of modern carpets.

With the increasing use of tacked down wall-to-wall carpeting in homesof all sizes, a problem has arisen both among professional cleaners andDo It Yourself householders, in the economical maintenance of suchcarpeting in a clean, bright condition. Wet scrubbing machines have beenproposed for cleaning the carpets directly on the floor, but to ourknowledge none of these machines successfully scrubs the carpet right upto the baseboard; resulting in much tedious and time consuming handwork, and such machines are clumsy and heavy to handle and the costthereof is extremely high.

it is one of the primary objects of this invention to provide a light,portable dry carpet scrubbing machine unit which is so-designed andconstructed that the same can be manipulated in corners and right up tothe baseboards and thus bring about correct cleaning of a carpet overthe entire area of a room, hallway, etc,

Another salient object of the invention is the provision of a carpetscrubbing machine'unit embodying a pair of horizontally disposedrotatable brushes with an electric motor arranged in a horizontal planeparallel with and between the brushes but above thebrushes and speedreducing gear trains located at one end only of the machine for drivingthe brushes in opposite directions from the motor, the arrangement beingsuch as to provide a compact, light, portable, balanced machine, inwhich one end thereof can be placed in direct engagement with thebaseboard for bringing the brushes up to the quarter round or the likeutilized for holding down the carpet.

A further important object of the invention is the provision of a novelguard comb arranged between the brushes and for engaging the bristles ofthe brushes to prevent the picking up of foreign objects by the brushes,such as the extension cord of the machine, should the brushes bemanipulated over the cord, the teeth of the comb being arranged in sucha manner as to not ride on the carpet whereby injury to the carpet willbe prevented, means being also provided to permit adjustment of the combas wear takes place on the brushes.

Another important object of the invention is the provision of amanipulating handle movable on an axis coincident with the axis of themotor, whereby the handle can be instantly swung from one side of themachine to the other, so that the machine can be reversed andadvantageously manipulated to bring about the correct positioning of themachine in corners and alongside walls, etc.

Another salient object of the invention is the provision of a twin brushcarpet scrubbing machine unit in which the weight and balance arecorrect so that the machine ice can be supported directly by the brusheson the carpet and whereby all supporting wheels, casters and the likeare dispensed with and whereby the brushes will engage the carpet withthe desired pressures.

A further object of the invention is to drive the horizontally disposedbrushes in opposite directions and toward one another, whereby to workthe cleaning material effectively back and forth through the pile of thecarpet and to prevent the undue throwing out of the cleaning powder etc.and to prevent the walking away of the machine from the operator duringmanipulation thereof.

A further important object of the invention is the provision of meanswhereby the brushes can be quickly removed and inter-changed so as toprevent uneven wear thereon and to prevent the bristles of the brushesfrom taking an undesirable set from constant rotation in one direction.

Another further object of the invention is the provision of a carpetscrubbing machine unit embodying an elongated manipulating handle and ahand grip positioned adjacent to the base of the machine unit withinterconnected controls for the motor carried by the handle and the handgrip, the elongated handle and its control being freely removablewhereby the machine unit can be expeditiously manipulated from the handgrip for cleaning stairway carpetsetc.

A still further object of the invention is the provision of means forholding the hand grip (and handle when used) against undesirableswinging movement, particularly during the use of the machine unit forscrubbing stair carpeting.

A still further important object of the invention is the provision oflike carpet scrubbing twin brush units with means for coupling the unitstogether to form a single machine, whereby to facilitate the quickcleaning of large areas and whereby the units can be quickly separatedfrom each other for independent use for easy manipulation in confinedareas.

A still further important object of the invention is the provision of anovel handle arrangement for the units, whereby when the units areconnected together a single effective manipulating handle is provided.

Another further important object of the invention is the provision ofmeans whereby when the units are coupled as one machine, only oneextension cord from one unit is utilized from an outlet box forsupplying current to the motor of each unit and whereby only themanipulation of one switch of one unit is necessary to control themotors of both units.

With these and other objects in view, the invention consists in thenovel construction, arrangement and formation of parts, as will behereinafter more specifically described and claimed and illustrated inthe accompanying drawings in which drawings,

Figure l is a perspective view of the novel carpet scrubbing machineunit;

Figure 2 is a similar view, but showing the opposite end of the unit;

Figure 3 is an enlarged central vertical sectional view through the unittaken on the line 3-3 of Figure 4, looking in the direction of thearrows;

Figure 4 is a fragmentary end elevational view of one machine unit withthe cover plate for the transmission and speed reducing gearing removed;

Figure 5 is a detail vertical sectional view taken on the line 55 ofFigure 4, looking in the direction of the arrows and showing moreparticularly the detachable mounting of one of the inter-changeablebrushes on its spindle or shaft, the view also showing the base lock forconnecting a pair of duplicate units together;

Figure 6 is a fragmentary central vertical sectional view through one ofthe machine units taken at right angles to Figure 3 and on the line 6-6of Figure 3, looking in the direction of the arrows, the viewillustrating the adjustability of the guard for the twin brushes and thelock for the handle;

Figure 7 is a detail vertical sectional view taken on the line 7-7 ofFigure 3, looking in the direction of the arrows illustrating the switchactuating mechanism for controlling the motor and the means fordetachably locking the manipulating handle on the machine.

Figure 8 is a detail horizontal sectional view taken on the line 88 ofFigure 7, looking in the direction of the arrows and illustrating thelock or latch for detachably holding the handle in position;

Figure '9 is a detail vertical sectional view through the handle bar ofthe handle showing the switch operating means in its locked position forholding the circuit closed through the operating motor;

Figure 10 is a fragmentary detail bottom plan view of the motor casingshowing the means employed for securing the holding collar for the motorcasing in an adjusted position;

Figure 11 is a front elevational view showing a pair of the unitscoupled together to form a complete machine for scrubbing a wide area,the view also showing the extension cord for one unit electricallycoupled with the control of the other unit;

Figure 12 is a fragmentary bottom plan view showing the handle bars ofthe two units in alignment and locked together, parts of the view beingshown broken away and in section to illustrate the inter-locking bolts;

Figure 13 is a view similar to Figure 12, but showing the bolts in theirextended released positions with the handle bars swung apart.

Figure 14 is a detail fragmentary vertical sectional view taken on theline 1414 of Figure 11, illustrating the coupling means in its projectedlocked position for uniting the bases of the units together;

Figure 15 is a fragmentary detail longitudinal sectional view taken onthe line l5-l5 of Figure 14, looking in the direction of the arrows andillustrating the bolt in its projected locked position for coupling thebases of the units together, and

Figure 16 is a diagrammatic view illustrating the wiring for a unit ofthe machine.

Referring to the drawings in detail, wherein similar referencecharacters designate corresponding parts throughout the several views,the letter M generally indicates my improved scrubbing machine (seeFigure 11), embodying a pair of identical machine units U. As the unitsU are of identical construction only one of such units will be describedin detail and it is to be understood that the complete machine M isutilized for scrubbing wide areas of the carpet and that independentunits U are utilized for cleaning small areas, and particularly forstair carpets and in confined places, such r as the corners and againstwall baseboards where ease of manipulation is essential and desirable.

Each unit U comprises a frame 20 which can be in the nature of a castingdisposed at one side of the machine and this casting also constitutes ahousing for the drive and reduction gearing, as will later appear. Theframe 20 includes a substantially triangular shaped inner plate 21having marginal side and bottom walls 22 and 23. A cover plate 24 isdetachably secured to the marginal side and end walls 22 and 23 andcompletes the housing for the gearing. The inner plate 21 has formedthereon at its upper end an inwardly directed cylindrical sleeve 25which constitutes the support for the electric drive motor 26.

The electric motor 26 will not be described in minute detail, but asclearly shown the same is arranged in a horizontal plane and includes asubstantially cylindrical motor casing 27 and the armature drive shaft28. The armature drive shaft 28 extends through a bearing boss 29 formedon the inner wall 21 of the frame and is rotatably mounted in suitablebearings 30 disposed in said boss and the armature shaft terminateswithin the housing and in a drive pinion 31 which can be secured to theshaft or formed directly thereon. The position of the motor forms animportant part of this invention, as brought out in the objects of thespecification and as will be hereinafter more frilly described and thecasing 27 is rotatable on the sleeve 25, for a purpose which will alsolater appear. In order ,to support the casing 27 for turning movement asupporting ring 32 is secured to the inner end of the sleeve 25 and thisring is provided with an outwardly extending annular flange 33 whichabuts up against the edge of the sleeve 25. Rotatably mounted on thesleeve 25 for turning movement is a flanged collar 34 and this collar isinternally threaded for receiving the threaded inner end of the motorcasing 26. By rotating the collar in the correct direction, the collarcan be turned up on the casing so as to bring the flange of the collartight against the flange 33 on the ring 32 on one side and the inneredge of the motor casing against the annular flange on the other side.To hold the collar 34 and the motor casing 26 against accidental turningmovement relative to one another after adjustment of the collar, theforward edge of the collar is provided with a series of indentations 36.A holding latch plate 37 secured to the ,motor casing by a screw 38 orthe like, can be placed in a selected indentation. From the descriptionso far, it can be seen that the motor casing 27 and the collar can beturned as a unit on the sleeve 25 and the ring 32. At desired times, themotor casing 27 and the collar 34 can be held against rotation on thesleeve 25 by a holding means 39. This holding means 39 will be laterdescribed.

Disposed at the lower corners of the triangular shaped inner plate 21are bearing bosses 40 which rotatably support outwardly extending spacedparallel spindles 41 for supporting the scrubbing brushes 42. Thespindles are also arranged in parallel relation to the armature shaft 28of the motor 26 and On each side of the motor, but in a plane below themotor. The spindles extend into the transmission housing as best shownin Figure 5, and these spindles have formed thereon or secured theretobeyond the frame plate 21 cylindrical barrels 43 having drive pins 44.The extreme outer ends of the spindles are provided with annular keepergrooves 45.

Each of the brushes 42 includes a solid hub 46 having embedded thereinthe brush tufts 47. This hub 46 is provided with an axial bore 48 whichis enlarged at its inner end to receive the barrel 43 and to define astop shoulder 49 for abutting engagement with the barrel. The shoulderis provided with openings 50 for receiving the driving pins 44 wherebyupon turning movement of the spindles 41 the brushes 42 will be rotatedtherewith. The outer ends of the bores 48 are provided with enlargements-to define chambers 51 which receive the terminals of the spindles andthese chambers have secured therein latch springs 52 which are adaptedto snap in the annular keeper grooves 45, whereby to retain the brusheson the spindles. By depressing the spring latches the same can be movedout of the grooves and the brushes can be readily pulled off of theirspindles. At this point, it is to be noted that the brushes are drivenin opposite directions and toward one another by means to be laterdescribed, and in order to compensate for wear on the brushes and toprevent the brushes from taking an undesirable set from being rotatedalways in the same direction the brushes can be inter-changed from onespindle to the other. The ends of the spindles 41 which extend into thegear housing have secured thereto gears 53. Novel means is provided forrotating the brushes in opposite directions and toward one another fromthe armature shaft 28 and the pinion 31 on the armature shaft and thegears 53 constitute a part of this drive. An important feature of theinvention is the proper balancing of the machine, so that the brushescan come into direct conasaegrss if; tact with the carpet or rug beingcleaned and whereby the machine is supported solely by the brushes andthe relationship of the motor 26 and the brushes 42 bring about thisbalance. Likewise, the drive and speed reducing mechanism is also arraned to bring about and to continue this proper balance. Secured to orformed on the frame wall 21 is a stub shaft 54 on which is rotatablymounted a gear set including a gear 55 and a pinion 56. The gear 55meshes with the drive pinion 31. It is to be noted that the stub shaft54 is at one side of and below the armature shaft and arranged below thestub shaft :5 are stub shafts 57 and 58. These stub shafts are disposedin the same horizontal plane and at equal distance on each side of thevertical axis of the unit. The stub shaft 57 has rotatably mountedthereon a gear set including a gear 59 and a pinion 60. The stub shaft558 has rotatably mounted thereon a similar gear set including a gear 61and a pinion 62. The gears 59 61 are inter-meshed and the gear 61 isdriven from the pinion 56. By this arrangement, it can be seen that thegears 58 and 61 are driven in opposite directions. The pinions 60 and 62drive a diverging train of gears 63 and 64 and the gears 53 for thebrushes 42 constitute a part of these trains. All of the gears are ofthe nylon type and hence the operation of the device is silent andlubrication of the gears is unnecessary. The motor is air cooled and thearmature shaft 28 can be provided with a fan, not shown, and the motorcasing with suitable inlet and outlet vents.

A cover and protecting plate 65 is provided for the brushes and the sameis preferably but not necessarily, formed from thermoplastic materialand the same includes a top wall 66 and an inner end wall 67. The topwall is shaped to present an attractive appearance and to conformsomewhat to the configuration of the brushes. The inner wall 67 can bereinforced by a metal plate 68 and screws 69 can be utilized forconnecting the plate to the wall 67 and the cover to the frame 20. Atthe end of the unit opposite from the frame 20 is 21 depending invertedV-shaped bracket 70, and the diverging depending legs of this bracketare secured by rivets or the like to an end flange of the top wall 66 ofthe cover 65. An end plate 71 is detachably secured to the cover platefor quick removal when it is desired to interchange the brushes 42. Asillustrated, see Figure 3, the end plate 71 can carry spring latches 72which are adapted to snap over a reinforcing plate 73 carried by the endflange of the top wall 66. The upper end of the V-shaped brackets 70 hasformed thereon an annular boss 74 which is fitted within an opening inthe end wall of the motor casing 27, and obviously, this bracket forms asupport for one end of the cover plate 65.

It is preferred to provide a guard 75 for the brushes 42 and this guardincludes a pair of spaced parallel comb bars 76 cmying outwardlyextending comb teeth 77. The outer ends of the comb teeth are curvedupwardly, as at 78, and extend into the tufts of the brushes 41 3. Thecomb teeth prevent the entrance of large particles into the brushes andform means for preventing injury to the electric cord of the machine (aswill later appear), should the machine be driven over the cord. The combbars 76 are connected at their ends by cross-bars 79 and these bars inturn carry upwardly extending supporting arms 80. The arms 80 slidablyextend through openings 81 formed in the cover plate and the upper endsof the arms 80 arerprovided with a series of openings 82. A supportingrod 83 is placed through desired openings and is suspended from theinner wall 21 of the housing 20 and the bracket '70. As illustrated, theinner wall or plate 21 is provided with sockets 84 for receiving one endof the rod 83 and in openings 85 in the bracket 70. By placing the rod83 at different points, the guard 75 can be raised and lowered tocompensate for wear on the brushes 42. If desired, a U-shaped guide 86can be formed on or carried by the wall 21 for receiving one by means ofa pivot pin 105 a handle 106.

of the arms so that swinging of the guard will be prevented relative tothe brushes and the casing.

Rigidly secured to one end of the motor casing 27 at a point remote fromthe supporting sleeve 25 is a housing 87 which forms a support forvarious parts of the unit, as will now be set forth. The lower edge ofthe housing is shaped to conform to the cylindrical configuration of themotor casing and can be riveted to the motor casing or secured theretoby screws 88. Formed on this housing is a laterally projecting hand grip89 and this hand grip extends over the motor casing and in spacedrelation thereto toward the supporting sleeve 25. This hand grip 89forms means for handling and manipulating a unit on stairways and thelike. Arranged within the housing 87 is a spring pressed normally openswitch 90 for controlling the flow of current to the electric motor 26.Rockably mounted on the housing, as at 91, below the hand grip 89 is aswitch handle lever 92 and this lever extends into the housing andengages the button of the switch 90. The switch lever handle 92 extendsunder the hand grip 89 and by pressing up on the switch handle 92 thebutton of the switch 90 can be depressed to close the circuit throughthe motor. Extending into the housing 87 is the extension or electricconduit cord 93 and this cord terminates in a plug 94 for connectionwith the outlet box of a house wiring circuit. Also carried by thehousing 87 is an outlet socket 95, for a purpose, which will laterappear. By referring to Figure 16 it can be seen that the feed andreturn wires 96 and 97 of the electric cord 93 are electricallyconnected to the terminals of the socket 'by branch wires 98 and 99 sothat when the switch 90 is closed a plug can be inserted into the socket95, as will later appear.

The upper end of the housing 87 is provided with a tapered opening 100in which is detachably fitted a tapered plug 101 rigidly secured to thelower end of the main manipulating handle 10?... The opening 100 isdirectly above the button of the switch 90 and the inner end of theswitch handle lever 92. The manipulating handle 102 is of an elongatedform whereby the unit can be manipulated over a carpet from a standingposition, by the operator. As best shown in Figure 3, the main handle102 is of a hollow construction and is preferably formed from a sectionof hollow tithing shaped to form the elongated handle portion 103 andthe laterally extending handle bar 104. At this time, it is to be notedthat the handle bar portion 104- extends inwardly over the motor and inspaced parallel relation to the hand grip 89. The inwardly directed handgrip portion 104 forms an important feature of this invention, as willlater appear.

As just brought out, the switch 90 is controlled from the switch leverhandle 92 and means is provided for also controlling the switch from thehandle bar 104-. Hence, the handle bar 104 has rockably mounted thereon.This handle can be of an arcuate shape for straddling the handle bar 104and the main part of the handle extends under the handle bar 104 forease of operation by the manipulator of the machine. The forward end ofthe handle termi mates in a finger 107 for engagement with a push rod108. This push rod slidably extends through the handle portion 103 andthis rod is guided in the sliding movement by guide plugs 109 secured insaid handle portion. Fastened to the push rod 108 is a washer 110.Confined be tween a guide plug 109 and the washer 110 is an expansionspring 111 which is coiled about the push rod and normally holds thepush rod in a raised elevated position.

The lower end of the push rod terminates directly above the button ofthe switch 90 and the inner end of the switch lever handle 92. Bypressing up on the body portion of the handle 106 the rod 108 can bedepressed against the tension of its spring 111 for actuating the switch90.

In many instances, it is desirable to hold the circuit closed throughthe motor without exerting continuous 7 pressure'on the handle 106locking the handle 106 in its raised position against the hand gripportion 104 with the rod 108 depressed. This means includes a headed pin112 which extends into the handle bar 104 and a button 113 slidablymounted on said handle bar 104. The button 113 carries a headed keeperscrew 114 which is adapted to engage and hold the head of the pin 112when the handle 106 is raised and when the thumb button 113 is slid tothe left (see Figure 9).

Under normal working conditions a machine unit U is manipulated from themain handle 102 and the unit is worked over the carpet and can be easilyguided close to the baseboard of a room and in corners and the like. Asthe housing 87 is carried by the motor casing 27 and as this housingforms a support for the handle, the handle can be swung easily with themotor from one side of a machine unit to the other and this facilitatesthe ease of use of a machine unit in corners and other close quarters.As previously brought out, the brushes 42 terminate close to one end ofthe machine unit and to the removable plate 71 and as this plate has asmooth outer face, the same can be placed directly up against abaseboard.

When a unit U is utilized for cleaning stair carpets, the main operatinghandle 102 can be removed from the opening 100 and the unit then can bemanipulated solely from the hand grip 89 which is close to the motor.

In order to prevent accidental removal of the main operating handle 102from the housing 87 and the opening 100 therein, a latch 115 is provided(see Figs. 7 and 8). This latch is rockably mounted on a pivot pin 116carried by the housing 87 and includes an inner cam shaped latching lug117. The collar or plug 101 which is securely fastened to the handle 102is provided with a keeper groove 118 and when the latch cam lug 117 isseated in this groove upward and outward movement of the handle from thehousing is prevented. By depressing the handle portion of the latch 115the cam lug part can be moved out of the groove 118. A spring 119 isemployed for normally holding the latch in its locked position.

During the operation of the unit from the hand grip 89, it is desirablein many instances to hold the motor against turning movement and meansis provided, as heretofore mentioned for holding the motor casing 27 andconsequently the hand grip 89 against free swinging movement. This meansincludes an annular brake band 121) arranged to bear on the innersurface of the motor casing 27 adjacent to the collar 34 and thesupporting sleeve 25. This band is split transversely, as at 121, and isnormally kept in its contracted non-holding position by a U-shaped leafspring, 122. This spring has its terminals riveted or otherwise fastenedto the brake band 120 on the opposite sides of the slot 121. Receivedbetween the legs of the U-shaped spring 122 is the flattened end 123 ofa rock shaft 124. This rock shaft 124 is mounted for turning movement inaligned bearing openings 125 and 126 formed respectively in the end wallor plate 21 and the supporting ring 32. The rock shaft has connectedtherewith a manipulating fingerpiece 127 which extends through a slotformed in the sleeve 25 and by turning the rock shaft 124 through thefingerpiece 127 the flattened end of the rock shaft can be positioned tospread the legs of the U-shaped spring 122 and thus bring about theexpansion of the brake band 120 into gripping contact with the motorcasing.

As brought out, the units U are adapted to be placed together to form acomplete machine for scrubbing large areas of carpets. The units areso-designed and constructed that the same can be placed end to end andlocked solidly together with the twin brushes of one unit inlongitudinal alignment with the twin brushes of the other unit, so as toform in effect continuous brushes. Likewise great importance is attachedto the formation and means is provided for of the handles 102 of theunits and particularly the handle bars 104 thereof. These handle barsproject laterally over the bases of the units and when the units areplaced end to end, the handle bars abut forming a continuous U-shapedmanipulating handle, see Figure 11. Means is provided for inter-lockingthe handle bars 104 of the two units U together to form the solidU-shaped handle for the machine and this means will now be described.Particular reference is invited to Figures 12 and 13. At this time,however, it is to be noted that when the machine units U are placed endto end and in abutting relation that the frames 20 of the machines areplaced together so as to leave the smooth clean ends of the unitsexposed for manipulation close to baseboards.

Now referring to the inter-locking means for the bandles, each handlebar 104 has slidably mounted therein a locking bolt 128. The inner endof each bolt carries a spring pressed headed thumb piece 129 and thisthumb piece normally projects through a longitudinal slot 130 formed inthe handle bar. The slot 130 is in the nature of a keyhole slot andhence the same is provided at spaced points with circular enlargements131 and 132 which constitute keeper portions for the spring pressedthumb piece 129 for the two positions of the bolt. Upon the depressingof the headed thumb piece 129 inwardly, the head thereof is movedinwardly beyond the keeper enlargements 132 so that the bolt can be slidback and forth and when the thumb piece is released the head thereofseats in a selected keeper opening 131 or 132 to hold the bolt againstsliding movement. The outer end of each bolt is provided with a hookshaped extension or knuckle 133 and when the bolt, of each handlebar104, is projected the bolts can be inter-locked by said knuckles orhooks through lateral movement of the handle bars toward one another,see Figure 13. When the bolts are interlocked and are in longitudinalalignment, both bolts are then retracted into their handle bars bymanipulation of the headed spring pressed fingerpiece 129 and when thefingerpieces reach the circular enlargements 132, the thumb orfingerpieces are released and the bolts are hid within the handle barsand the handle bars will be firmly uni-ted for synchronous movement.When it is desired to release the handle bars from one another, thebolts are again projected and the handles are moved laterally away fromone another. When a single unit U is utilized then the bolt of itshandle bar is slid all the way in until the head of the thumb piece 129reaches the circular enlargement 131. At this time, the thumb piece canbe released and the bolt is held entirely within the handle bar (seeFigure 3). In this instance the bolt then forms a closure for the hollowhandle bar 104.

It is also extremely desirable to lock the bases of the two unitssolidly together and novel means is provided for this purpose. Thislocking means is best shown in Figures 4, 5, 14 and 15.

Each unit U is provided on one side of the frame 20 with a keeper socket134 and on the other side with a sliding retractable locking bolt 135.The keeper socket 134 has extending through the same, transversely, arigid keeper pin 136, the purpose of which will now appear.

The bolt 135 carries a radially extending manipulating handle 137 whichslidably extends through a bayonet slot 138 formed in one side wall 22of the frame. The outer end of the bolt 135 is provided with a knuckleor book 139, which is adapted to engage the keeper pin 136.

Considering that the units U are placed in abutting relation, as shownin Figure 3, with the bolt 135 of each unit in its retracted position,then the bolts of both machines are slid outwardly and into the sockets134 of the units. At this moment, the hooks or knuckles 139 slide pastthe keeper pins 136 and when the bolts are slid outward to their fullestextent, the same are turned so as to move the hooks or knuckles 139 overthe keeper pins and this turning movement is permitted in view of theformation of the bayonet slots 133. In order to maintain the bolts intheir projected position, each bolt is provided with a keeper depression140 which is brought into registration, upon the turning of the boltwith a spring pressed keeper ball 141. A leaf spring 142 is employed fornormally holding the ball toward the bolt and the tension of the springis such that the ball will spring out of the keeper recess 140 upon theforcible turning of the bolt. When the bolt is turned to permit theretraction thereof and the same is slid inwardly, a second keeper recess143 is then brought into registration with the ball 141 and the ballthen functions to hold the bolt against outward sliding movement. Bythis arrangement, it can be seen that the bases of the machines arefirmly locked together on each side and when the bases are so locked andthe handles 102 are inter-locked then the machine M can be freelymanipulated.

When the machine units U are coupled together as a single working unit,the electric plug 94 of one unit is plugged into the electric socket 95of the other unit (see Figure 11). Thus only one electric extension cordneed be connected to the house circuit and both units can be controlledfrom one operating handle 106 of one machine.

From the foregoing description, it can be seen that twin brush unitshave been provided in which all parts are so-arranged that a balanceddevice is had and one in which all supporting rollers, casters and thelike are eliminated and whereby the brushes can rest directly upon thecarpet to be scrubbed.

The twin brushes rotating in opposite directions throw the cleaningpowder back and forth between the same and effectively work the cleaningpowder through the pile or nap of the carpet.

By forming the machine M in two units, not only is ease of operation hadin confined places, by using a single unit, but the machine can beconveniently carried into and out of a home by separating the units andgrasping the hand grips 89 one in each hand.

Various changes in details may be made without departing from the spiritor the scope of this invention, but what we claim as new is:

1. A carpet scrubbing machine unit comprising a. frame, a pair ofhorizontally disposed scrubbing brushes rotatably mounted on the frame,a horizontally disposed electric motor on the frame, means located atone end of the frame only for operatively connecting the motor with thebrushes for rotating said brushes, said brushes extending substantiallythe full width of the unit and to the extreme end of the unit remotefrom the means for rotating said brushes, whereby said end remote fromthe driving means can be placed directly against a wall for cleaning acarpet close up to said wall, a supporting member rotatable around themotor on an axis coincident with the axis of the motor, an elongatedmanipulating handle detachably mounted in the support, and a hand gripon the support arranged in close proximity to the motor.

2. A carpet scrubbing machine unit as defined in claim 1, and means forholding the support in a selected posinon.

3. A carpet scrubbing machine comprising a pair of identical units, eachof said units including a frame, a pair of horizontally disposedscrubbing brushes rotatably mounted on the frame for direct engagementwith the carpet being scrubbed and for supporting the machine on thecarpet, an electric motor on the frame, means for simultaneouslyrotating the brushes, from the motor, an elongated handle mounted on theframe movable from one side of the unit toward the other with the upperend of the handle terminating in a laterally projecting handle bar, saidunits having plain end faces adapted to be placed in abutting relation,and means detachably locking the units together with the handle bars inalignment and abutting to form a continuous grip whereby the units 10can be manipulated together as a single machine or as independent units.

4. A carpet scrubbing machine including a pair of identical units asdefined in claim 3, and said locking means including means fordetachably locking the frame of the units together and means detachablylocking the handle bars together.

5. A carpet scrubbing machine including a pair of like identical unitsas defined in claim 4, and said handle bars being of a hollowconstruction and said locking means for the handles including boltsslidable in the hollow handles and projecting into the handle bars ofeach other when the handle bars are in alignment.

6. A carpet scrubbing machine unit comprising a frame, a pair ofhorizontally disposed scrubbing brushes rotatably mounted on the frame,a supporting sleeve on the frame projecting over and between thebrushes, an electric motor for driving said brushes including a motorcasing rotatably carried by the sleeve, a hand grip carried' by themotor casing and located in close proximity thereto, and an elongatedmanipulating handle carried by the motor casing, the hand grip and thehandle being movable with the motor casing on the sleeve, and means forholding the motor casing against turning movement and in a selectedlocked position.

7. A carpet scrubbing machine unit as defined in claim 6, and said lastnamed means including a brake band arranged within the motor casinghaving a transverse slit, a U-shaped spring connecting the ends of thebrake band on opposite sides of the slit and holding the band in acontracted position from out of engagement with the casing, and arotatable shaft carried by the sleeve having a flattened terminaldisposed between the legs of the U-shaped spring for spreading said legswhen the shaft is in one position for expanding the brake band againstthe motor casing.

8. A carpet scrubbing unit comprising a frame, a pair of horizontallydisposed scrubbing brushes rotatably mounted on the frame for directengagement with the carpet to be cleaned and for supporting the unit onthe carpet solely, a horizontally disposed electric motor on the frame,the brushes and motor being arranged in parallel relation, means forsimultaneously rotating the brushes in opposite directions toward oneanother from the motor, said motor being disposed centrally of thebrushes and above the peripheries of the brushes, whereby said brushesare disposed in close proximity to one another for working cleaningmaterial back and forth between the same and through the pile of thecarpet being cleaned, and a supporting member rotatable around the motoron an axis coincident with the axis of the motor, and a manipulatinghandle carried by the supporting member and movable therewith.

9. A carpet scrubbing machine unit comprising a frame, a pair ofhorizontally disposed scrubbing brushes rotatably mounted on the framefor direct engagement with the carpet to be cleaned and for supportingthe unit on the carpet solely, an electric motor on the frame, means forsimultaneously rotating the brushes from the motor, a mounting disposedbetween and above the lower. faces of the brushes and carried by theframe, and outwardly projecting oppositely extending comb teeth carriedby the mounting terminating in upwardly extending ends projecting intothe bristles of the brushes adjacent to but spaced from the lower facesof the brushes, whereby to prevent the gathering of the carpet andforeign objects into the brushes.

10. A carpet scrubbing machine unit as defined in claim 9, and means foradjusting the mounting and the comb teeth in a horizontal plane relativeto the carpet and the peripheries of the brushes to compensate for wearon the brushes.

11. A carpet scrubbing machine comprising a pair of identical units,each of said units including a frame, a pair of horizontally disposedscrubbing brushes rotat- .12 Beach Mar. 15, 1932 Eng'berget a1. May 26,1936 :Osborn Ian. 25, 1949 Sears July 17, 1951 Barn'hart June 17, 1952Turner Apr. 7, 1953 Burnham 'Mar. 23, 1954 Johnson Mar. 30, 1954Ve'rhagen Apr. 20, 1954 Peterson June 15, 1954 Sherman Oct. 11, 1955FOREIGN PATENTS 'GreatBritain Nov. 17, 1932 France July 25, 1925 OTHERREFERENCES Product Engineering, article by Stott, pp. 103-107,

1 1 ably mounted on atlre frame for-direct engagement 'with 13849218 thecarpet being scrubbed, an electric motoronthe-frame, 2,041,748 means forsimultaneously rotating :the brushes from the 2,460,236 motor, anelongated manipulating handle on the frame, 2,560,993 said units beingpositioned side by side with the brushes 5 2,600,608 of one unit inparallel relation to the brushes of the 2,633,597 other unit, and meanslocking the units together for 2,672,634 simultaneous operation, and:said locking means includ- 2,673,366 ing means for connecting theframes together and the 2,676,067 handles together. 10 268038682,720,119 References Cited in'the file of this .patent UNITED STATESPATENTS 1,147,440 Roach July 20, 1915 15 1,197,915 Dance Sept. 12, 19161,417,768 Radimak May 30, 1922 1,569,167 Anderson Jan. 12, .1926

1,607,500 Agar Nov. 16, 1926 1,770,643 Giambertoni July 15, 1930 20December 1946.

